Trying to save an ancient broken down Carlsbro amp
I have an old Carlsbro bass amp (Linear Bass 100) which has recently broken down and it's at the workshop with some doubt about whether it can be repaired. One of the components that has blown is a resistor on the power supply board and it is so burned out that the engineer cannot identify what rating it is supposed to be, and therefore what ohmage resistor to replace it with.
We have been looking for a circuit diagram for this type of amplifier (or other info that could help in its repair), so far with no success. I tried emailing Carlsbro but the people I got through to don't have the necessary information or components, due to the age of the model. I bought it second-hand in 2000/2001 and it was some years old then, so it is a quite ancient (though having been of sturdy service)
I would like to save it from the scrap heap if I can, not least due to my modest financial circumstances.
Does anyone have any info or ideas?
I would be most grateful,